It is believed that examples of known fuel systems use a bladder to reduce fuel vapor build up within a fuel tank.
It is believed that examples of fuel systems in compliance with fuel emission laws use a bladder and check valves to vent the fuel vapor to a charcoal canister.
It is believed that other examples of fuel systems control the rate of evaporative emission to the charcoal canister by sensing the vapor pressure buildup in a fuel tank.
It is believed that still other examples of fuel systems control the rate of fuel vapor build up by pressurizing a bladder of a fuel tank to attenuate the formation of fuel vapor.
It is believed that the anticipated usage of alcohol based fuels such as methanol or alcohol in the future will require a more reliable and robust fuel system to prevent emission of vapor and fuel.
According to the present invention, a fuel delivery system can purge fuel vapor without the use of a charcoal vapor canister. According to one embodiment of the present invention, a failsafe fuel tank is provided. According to yet another embodiment, a fuel module to detect and prevent leakage of fuel vapor or liquid is provided. According to another embodiment of the present invention, a method is provided to detect fuel leaks and to prevent the leakage of fuel.
The present invention provides a fuel delivery system to an internal combustion engine. The fuel delivery system comprises an internal combustion engine; an emission computer; and a fuel tank. A flexible membrane is disposed within the fuel tank, the membrane separating a first chamber and a second chamber. A fuel pump being coupled to one of the first and second chambers, the fuel pump adapted to supply fuel to the internal combustion engine. A first valve communicates with at least one of the first and second chambers, the first valve assembly adapted to vent air from one of the first and second chambers when fuel is pumped into or out of the fuel tank. A second valve in communication with the other one of the first and second chambers, the second valve adapted to purge air and fuel vapors without a charcoal canister during an operation of the engine; a sensor is disposed within one of the first and second chambers and connected to the emission computer, wherein the sensor is responsive to the presence of air in one of the first and second chambers.
The present invention further provides a fuel storage module. The fuel storage module comprises a first container with at least one open end; a second container with at least one open end. A flexible membrane being disposed between the open ends of the respective first container and the second container. A fuel pump being coupled to one of the first and second containers. A first valve communicates with at least one of the first and second containers. A second valve communicates with the other one of the first and second containers, and the second valve not in communication with a charcoal vapor canister. A sensor is disposed within one of the first and second containers, wherein the sensor senses the presence of air in one of the containers.
The present invention additionally provides for a fuel vapor control system for an internal combustion engine. The system comprises a fuel tank; a flexible member being disposed within the fuel tank, the member separating a first compartment and a second compartment; a fuel pump being coupled to one of the first and second compartments; a first valve communicating with at least one of the first and second chambers; a second valve communicating with the other one of the first and second chambers and in further communication with a vacuum source, the second valve not in communication with a vapor canister; and a sensor being disposed within one of the first and second chambers, wherein the sensor is a liquid-air discriminator.
The present invention also provides for a method of determining leaks in a fuel tank. The method comprises providing fuel in a storage volume in the absence of air, and detecting an entry of air in the fuel storage volume.
The present invention further provides for a method of operating a fuel-vapor purge system. The vapor system includes a fuel storage chamber and an air chamber in a fuel tank. The method comprises providing fuel to the storage chamber to allow the formation of fuel vapors in the fuel storage chamber; expelling air and fuel vapors in the storage chamber without communicating to a charcoal vapor canister; and sensing the entry of air into the fuel storage chamber.
The present invention additionally provides for a failsafe method of retaining fuel within a fuel tank. The fuel tank includes a fuel storage chamber and an air chamber. The method comprises depressurizing the fuel storage chamber to a pressure lower than ambient air pressure; preventing air from venting out of the air chamber; and retaining fuel in the storage chamber upon a rupture of the fuel storage chamber that allows outside air to enter the storage chamber.